An unusually cold storm for the season brought significant travel problems to the mountains. Strong thunderstorms with large amounts of small hail and heavy rain caused for slippery roads and local flooding in the northern San Joaquin Valley.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS STO wrote it up.
An unusually cold storm for the season brought significant travel problems to the mountains. Strong thunderstorms with large amounts of small hail and heavy rain caused for slippery roads and local flooding in the northern San Joaquin Valley. These thunderstorms also produced multiple funnel clouds. Accumulating small hail was also observed on Interstate 5 south of Anderson, CA.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sacramento, CA wrote its last area forecast discussion before the first event at May 16, 2:40 AM PST, 5 hours 23 minutes earlier.
Area Forecast Discussion National Weather Service Sacramento CA 340 AM PDT Thu May 16 2019 .SYNOPSIS... Showers and isolated thunderstorms today with snow and travel issues over the Sierra passes. Gusty south winds in the Sacramento valley. Mountain showers mainly ending on Friday. Rain and mountain snow returns Saturday afternoon. Showers Sunday with shower threat continuing through middle of next week. && .DISCUSSION... Back edge of cold frontal band now working its way eastward through the Sacramento and northern San Joaquin valley with a shield of precipitation across the eastern half of the CWA. Surface observations and Radar indicate snow levels at around 7000 feet at this time so summits likely being impacted. Breezy south winds in the Sacramento valley have dropped off some now that the front has passed eastward but expecting an increase in wind this afternoon as the upper low associated with the front moves inland. Showers will be a pretty good bet most areas of the CWA today as the upper low slides across the north state. Enough instability is indicated for a slight threat of thunderstorms over the region as well. Colder air moving into the region will bring down snow levels today with snow levels down to about 5000 feet by mid morning. Daytime highs today will drop as well down to as much as 20 degrees below normal for the date. The main upper low is forecast to shift into the Great Basin over night so most areas should see decreasing showers. By Friday afternoon the shower threat will linger over the Sierra crest and northern mountains but the remainder of the CWA should see clearing. Most areas should see an uptick in daytime temperatures as a shortwave high pressure ridge slides over the west coast. Friday night looks dry under this ridge most areas but GFS and NAM both want to throw a shortwave across the northwest corner of the state for a sLight threat of showers northern Shasta county. Next Pacific frontal system pushes inland on Saturday for another round of precipitation over forecast area. This frontal system should move east of the forecast area by Sunday morning with Sunday seeing mainly shower activity through the day. This system currently appears weaker than the system currently moving through the region but with snow levels expected to be below pass levels, travel impacts are again likely. && .EXTENDED DISCUSSION (Monday THROUGH Thursday) Unsettled weather, below average temperatures, and breezy winds continue through next week. A closed low moving across California towards the southwest US Monday may briefly allow for dry conditions in the Valley before ensemble means depict another trough axis moving across NorCal Tuesday night. Chances for showers continue across the Sierra and northern mountains early next week with snow levels Monday near 6000 feet. Snow levels will be on the rise Tuesday and through the rest of the week as the next system moves into the area by mid-week. Temperatures slowly increase just below normal values by Thursday, with Valley highs in the upper 70s by Thursday afternoon. Chances for showers continue across all of NorCal through the end of the week. && .AVIATION... Showers will continue across the area over the next 24 hours bringing periods of mainly MVFR ceilings and visibilities. Thunderstorms will be possible between 18-03Z, with IFR conditions possible with any storm over a site. Southerly winds increase in the Sacramento Valley this afternoon with gusts up to 30 knots possible. The strongest gusts look to be north of KSAC. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 6 AM PDT Friday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. Wind Advisory until 5 PM PDT this afternoon for Central Sacramento Valley-Northeast Foothills/Sacramento Valley-Northern Sacramento Valley-Southern Sacramento Valley. &&
The San Francisco radar (KMUX), 73 km away, was scanning. The volume nearest the first event began at 16:03 UTC.
4 funnel cloud, 2 winter weather, 1 heavy snow, 1 heavy rain, 1 flash flood. Local standard time, as filed.
Photos and reports on social media indicated a funnel cloud in the Patterson - Crows Landing area in Stanislaus County around 9 am PDT.
A trained spotter reported a funnel cloud in Oakdale in Stanislaus County around 3:30 pm. No damage or touchdown was observed.
A COCORAHS observer reported 12 inches of snow in 24 hours at elevation 6768 on the morning of May 19th.
On May 19th, at an elevation of 4400 feet, a CoCoRaHS observer reported 2 inches of snow.
A trained spotter located in Cobb reported 1.5 inches of snow at elevation 4700 feet on May 19th.
There was 1.44 inches of rain reported at a HADS Stockton Fire Station in 1 hour. Some local roadway flooding was observed in the area.
There were numerous reports of roadway flooding in Stockton due to heavy rain and large amounts of small accumulating hail on May 19th. Law enforcement reported March Lane and Quail Lakes being shut down along with Hammer Lane between Lorraine Ave and Girardi Way due to flooding.
A funnel cloud was reported with a storm north of Tracy around 5:45 pm PDT on May 19th. No touchdown or damage was observed.
A second funnel cloud was reported with a storm north of Tracy around 5:50 pm PDT on May 19th. No touchdown or damage was observed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2019Every state in 2019This day in weather historyWarnings in California, May 2019
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 827868, 828541, 828564, 832755, 832753, 828543, 828545, 828546, 828558.